Botany is based on fixed genera.

As one sits here in summertime and listens to the cuckoo and all the other bird songs, the crackling and buzzing of insects, as one gazes at the shining colors of flowers, doth one become dumbstruck before the Kingdom of the Creator.

The names of the plants ought to be stable [certa], consequently they should be given to stable genera.

Nature does not proceed by leaps.

A herbarium is better than any illustration; every botanist should make one.

It is not God, but people themselves who shorten their lives by not keeping physically fit.

It is the genus that gives the characters, and not the characters that make the genus.